Diaphragm seal for turbines



Feb. 8, 1949. I c R. SQDERBERG 2,461,243

' DIAPHRAGM SEAL FOR TURBINES I Filed Aug. 25, 1944 2 Sheets-Sheet 1 FIG.

INVENTOR so 64 66 5s 54 Feb. 8, 1949.

Filed Aug. 23, 1944 C. R. SODERBERG DIAPHRAGM SEAL FOR TURBINBS 2 Sheets-Sheet 2 3 2 INVENTOR Patented Feb. 8, 1949 UNITED STATES PATENT OFFICE 2.401.243 DIAPHRAGM sear. son 'ruanmss Carl R. Soderberg, Weston,

Mass assignor to United Aircraft Corporation, East Hartford,

Conn.,

a corporation of Delaware Application August 23, 1944, Serial No. 550,980 2 Claims. (Cl. 253-69) This invention turbines.

Theseal at the inner edge of the turbine diarelates-to diaphragm seals for phra'gm consists usually of a split ring carried by Because of the interfitting cylindrical sleeves in a Ljungstrom type seal it has been impossible to assemble this type of seal on the turbine. diaphragm if the turbine casing is split for radial assembly on the rotor. A feature of this invention is an arrangement of the rotor and casing to permit assembly of a seal or this type.

A feature of the invention is a labyrinth seal for the turbine diaphragm having interfitting substantially cylindrical elements mounted on the rotor and diaphragm. Another feature is the use of continuous seal members rather than split seal members.

Other objects and advantages will be apparent from the specification and claims, and. from the accompanying drawings which illustrate an embodiment of the invention.

Fig. 1 is a sectional view through the turbine.

Fig. 2 is a sectional view on a larger scale of the diaphragm seal.

The turbine shown includes a casing l8 built up of rings l2, l4, l8 and i8 supported by radial pins 28 in a housing 22. These pins which are all in substantially the same plane and which constitute the support for the casing within the housing. engage bores in bosses 24 in one ring l4 of the casing. Rotor 28 within the casing has a number of rows of blades 28 alternating with the rows of nozzles 88 in the casing.

Housing 22 has a head 84 which forms a part or the housing and supports a bearing sleeve 38 for the front end of rotor 28. At the other end of the turbine, the housing 22 supports a mounting 88 within which is a bearing 48 for the rotor. Mounting 88 has a number of legs 42 engaging with radial pins 44 which locate themounting within the housing.

Rotor 28 is made up of a number of discs, 48. 48, i8 and 82, each or which is substantially a constant stress disc, and shaft-forming end elevments 84 and 88. The discs and the shaft ele- 2 ments are allheld together by a central bolt 88. The ends of the bolt are positioned within the end elements 84 and 58 and are connected to the end elements by threaded sleeves 88 and 82. Each sleeve 88, 62 has inner and outer threads 84 and v 86 engaging respectively with cooperating threads on the bolt and on the and elements. On one of the sleeves (sleeve 88 as shown) the inner and outer threads may diifer in pitch so that as the ring is screwed into place, a substantial tension i may be applied to the bolt.

Since the casing is built up 01 casing rings bolted together each having a row of nozzles, and since the rotor is built up of discs, each having a row of blades, it is apparent that the turbine is adapted for endwise assembly. To assist in aligning the discs and to prevent relative rotation in operation during assembly, each disc has pro- Jecting annular flanges 88 and 18 on opposite sides having interengaging elements preferably in the forni of face splines 1| cooperating with similar elements on the adjoining disc. Similarly, the inner ends 01! shaft elements 54 and 58 have i'ace splines cooperating with splines 'II on the end discs. Stability of the rotor may be maintained by projections 12 on the bolt engaging radial slots 18 in disc 48.

Gas enters the first stage nozzles of the turbine through an inlet scroll 14 which is bolted on or otherwise attached to the end of casing l8. Leakage of power gas past the outer ends 01 the blades is prevented by seals I8 which may --be positioned between adjoining casing rings. Leakage of power gas past the inner edges of the diaphragm 18 extending inwardly from each row of nozzles isprevented by a labyrinth seal 88. Gas from the turbine discharges through a duct 82 connected to the end casing ring and surrounding the rear bearing mounting. 4

The diaphragm seal between successive stages of the turbine rotor is a Ljungstrom type of seal and includes a ring 84 mounted on the outer sur-v faces of the opposed flanges 88 and I8 of adjoining discs. This ring, which may be locked against rotation by a pin 88 extending from one of the flanges. has an integral cylindrical flange 88 on its outer surface with the free end of the flange forming an inwardly extending sealing rib 88. Cooperating with sealing rib 88 is a cylindrical flange 82 on a ring 84 attached to the inner periphery of the diaphragm l8. Flange 82 has its free edge located between flange 88 and ring 84 so that sealing rib 88 may engage the outer surface 01' flange 82. An inwardly exmenace sealing rib on flange I! may engage the outer surface ring 04.

Since the rotor is split and since the casing is built up of a number of annular rings, it is apparent that this type of seal, which requires axial assembly, may=be mounted between the adjoining turbine discs, as shown, during assembly of the turbine. Both rings 84 result, be continuous unsplit structures.

It is to be understood that the invention ls not limited to the speciflc embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as deflned by the following claims.

I claim- 1. A turbine rotor including a number of discs each having a row of blades extending substantially radially from the periphery thereof, and each having annular flanges on opposite sides thereof concentric to the discs, each of said discs having a central opening with the annular flanges of such a dimension as to be radially spaced between the central opening and the periphery oi the discs, said flanges being in interengagement and having means thereon for piloting the discs with respect to one another, and means extending through the central openings in the discs and holding said discs in endwise engagement, an annular sealing element located between adjoining discs and supported on the outer surfaces of said flanges, said sealing element being in the form substantially of a cylinder having engagement with both of the flanges adjacent thereto. and a cylindrical sealing flange connected to and spaced from the outer periphery of the cylinder, in combination with a turbine casing having rows of nozzles alternating with the rows of blades, and diaphragms extending inwardly from the nozzles and located between adjoining discs, and a sealing element carried by each diaphragm having a substantially cylindrical flange fltting between the flange on the rotor sealing element and the outer periphery of the cylinder part of the rotor sealing element.

2. A turbine rotor including a number of discs and 84 may, as a each having a row of blades extending substantially radially from the periphery thereof, and each having annular flanges on opposite sides thereof concentric to the discs, each of said discs having a central opening with the annular flanges of such a dimension as to be radially spaced between the central opening and the periphery oi the discs, said flanges being in interengagement and having means thereon for piloting the discs with respect to one another, and means extending through the central openings in the discs and holding said discs inendwise engagement, an annular sealing element located between adjoining discs and supported on the outer surfaces oi said flanges, said sealing element being in the form substantially of an unsplit cylinder having engagement with both of said flanges, and a cylindrical flange connected to and spaced from the outer periphery of the cylinder, in combination with a turbine casing having a number of rings each having a row of nozzles alternating with the rows of blades, and

' diaphragms extending inwardly from the nozzles and located between adjoining discs, and a sealing element in the form of a continuous ring carried by each diaphragm and having a substantially cylindrical flange thereon to flt between the sealing flange and the outer periphery of the cylinder part of the sealingelement on the rotor.

CARL R. SODERBERG.

REFERENCES CITED The following references are of record in the 

